Woofer placement

dynamo

Looking for a consensus from the experts (you guys) on this.

If I was building a full-ish range floor standing speaker with two 8” subs per speaker built in, crossed over to an 8” midbass around 100hz, would it be better to put both woofers on the front, both close to the floor with one on front and one on back, or otherwise?

My perceived pros of each:

Both in front:
Better integration on upper bass
Better sensation of impact on upper bass
Looks better (to my eyes)

Front/back by floor:
Boundary reinforcement
Force cancellation
Perhaps better room integration of bass

Just conceptualizing a build and can’t get past this..thanks gents!

jhollander

At 100 Hz I'd say aesthetics rule. You should never build something that doesn't look good to you, it's takes too much effort.

dynamo

Thanks John. Aesthetics are pulling me toward the two on the front unless there is a clear undisputed reason to do otherwise. I just feel like three 8” drivers on the front would look intense!

jhollander

Dan Neubecker used the TB RBM woofers in the Scimitars.
https://projectgallery.parts-express.com/speaker-projects/the-scimitars/

They were low mounted and the rear was reverse mounted for the hypothetical distortion cancellation and floor gain. I think the low mounted single woofer is a design challenge to be overcome. You are probably getting enough low end boost with the two woofers. I bet the tweeter spl is going to be close.

dynamo

Those are pretty cool speakers. I remember when he posted those, it got me thinking about the reverse mounted opposed driver. I have considered that multiple times since but never could pull the trigger on a design. It seems to help that those TB woofers are shallow with a large diameter magnet; looks good.

Good point in additional boundary gain. I’d rather have a little spare spl to play with on the tweeter, so no need for the extra gain.

4thtry

I'm certainly not an expert, but this would be my suggestion. Sorry for the poor drawing. Two woofers on the front, bottom one 14" above the floor. With a 100Hz xover, I don't think you would lose any woofer gain by moving the woofers higher off the floor. As I understand it, the port could also be moved up higher, perhaps behind the tweeter, without any loss in low frequency gain. At 100hz and below, floor boundary gain would be the same 6dB or so, regardless of placement height.

jhollander

In terms of boundary reinforcement I like the low mounted port, rear mounted to hide any box resonances

dcibel

If you want the most output put the woofers at floor level, otherwise just do what you think looks nicest.

dynamo

Thanks for the advice guys!

Kornbread

@jhollander said:
In terms of boundary reinforcement I like the low mounted port, rear mounted to hide any box resonances

Bottom port?

dynamo

@Kornbread said:

@jhollander said:
In terms of boundary reinforcement I like the low mounted port, rear mounted to hide any box resonances

Bottom port?

That’s a good thought. Probably can save some port length in the cabinet with the distance between the port and the floor to the edges of the cabinet.

I know there are lots of reasons on paper why it is probably inferior to other placement but I’ve always been partial to front ports though.

jhollander

Out the bottom of the box port is hard to predict the final tuning so leave someway to adjust the length.

Front port is nice as sometimes you can measure part of the response gain with the woofer far field. The port round over in a solid wood front baffle is always cool.